My prior U.S. Pat. No. 3,201,548, issued Aug. 17, 1965, showed a standard commercial construction of a thermostatic switch and a tilt-responsive switch. This attitude responsive switch was dependent upon the position of a swinging pendulum mounted on a resilient contact blade. The movement of the pendulum or the movement of a temperature responsive means, namely, a bimetal, could actuate one set of contacts. Such combined thermostat and attitude responsive switch was useful in devices such as electric room heaters wherein it was desired to control the temperature of the air warmed by the heater and yet the room heater might be tipped over which could be a fire hazard, hence, the attitude responsive switch would disconnect the electrical circuit to make a safe appliance.
It has been found that under long use the contacts actuated by the temperature responsive means might malfunction. For example, this might be that the contacts would weld together due to the creep action initiated by the bimetal. The homeowner might not be aware that the contacts had welded closed and might continue to use the room heater even though the thermostat was no longer functional. Under such a condition the attitude responsive pendulum also would not be functional because if the room heater were tipped over and the pendulum tried to actuate the contacts, the welding together thereof meant that the circuit could not be opened.
In other prior art patented systems flat irons have been controlled with both a temperature responsive means and a tilt responsive means so that when the flat iron was rested on its heel, the tilt responsive means controlled the contacts. Some of these designs had two contacts in series with one actuated by the temperature responsive means and the other actuated by the tilt responsive means, or else both actuated by both responsive means, yet in no case was one set of contacts actuated by one responsive means and actuable by the other responsive means as a standby set of contacts.
Electric room heaters have also had switches which are controlled by temperature responsive means and by a means responsive to the tilting of the entire electric heater, namely, a plunger which can contact the floor. In one such patented construction two separate contacts were provided, one for the plunger and one for the bimetal; but these contacts were on opposite sides of the stack which mounted all of the flexible blades. In another construction two flexible blades were on opposite sides of a rigid blade, with all three blades carrying contacts and with a plunger actuating one flexible blade and a bimetal actuating the other flexible blade; but in no case was there any standby actuation of an additional set of contacts.